Brent Ellerbroek

TL;DR: In this paper, the authors proposed a sparse minimum-variance reconstructor for a conventional natural guide star AO system using a sparse approximation for turbulence statistics and recognizing that the nonsparse matrix terms arising from LGS position uncertainty are low-rank adjustments that can be evaluated by using the matrix inversion lemma.

TL;DR: The Gemini multiconjugate adaptive optics system (GeMS) at the Gemini South telescope in Cerro Pachon is the first sodium-based multilaser guide star (LGS) adaptive optics as discussed by the authors.

TL;DR: Adaptive Optics (AO) will be essential for accomplishing many, if not most, of the science objectives currently planned for Extremely Large Telescopes including GMT, OWL, and TMT as mentioned in this paper.

TL;DR: In this paper, the authors analyze the fundamental limitations of MCAO systems and demonstrate that the ultimate limitation is due to the vertical discretization of the correction, which becomes more severe with increasing compensated field of view or decreasing wavelength, but does not depend at first order on the telescope aperture.

TL;DR: In this paper, a multigrid preconditioned conjugate-gradient (MGCG) iterative scheme for computing open-loop wavefront reconstructors for extreme adaptive optics systems is introduced.